Health Report.When parents go to work,their young childrenoften spend the day in child care.That contact with other childrencan make it easier to get sick.But new research suggests thatthis might have a protective effecta few years laterwhen children start school.A research team lookedat data from a large study.That study followed the healthof a group of Canadian childrenfor almost their first ten years of life.Sylvana Cote at the Universityof Montreal led the research team.She says some of the childrenwere more likely to get sickfrom the kinds of infectionscommonly passedaround a day care center.But she says these childrenwere also more likelyto avoid infections when theyentered elementary schoola few years later.SYLVANA COTE: "Children who startedchild care early -- that is,before two and a half years-- and who attended child carewhere there were a large groupof children, they have lower ratesof infections than childrenwho either never went to day careor children who wentto small-group day care."Sylvana Cote says her studywas not really designed to explainwhy children who started day careearly with many other childrenhad fewer infections later.But she says there isa non-medical reason whygetting sick early might be better:it reduces the risk of havingto stay home from school.SYLVANA COTE: "We argue in the paperthat missing school when you'restarting to learn to reador when you learn to writemay be more problematicfor the future academic trajectorythan missing day care days."The research appearsin the Archives of Pediatricand Adolescent Medicine, a journalof the American Medical Association.Some diseases can beprevented by vaccines.This month, the WorldHealth Organization launchedthe first vaccineever developed for Africa.The vaccine is designedto provide ten years of low-costprotection against meningococcal A.This bacterial form of meningitiscan cause brain damage and death.Major epidemics strike Africaevery seven to fourteen years.Children and young adultsare the hardest hit.Last year, an outbreakacross sub-Saharan Africakilled more than five thousand people.The WHO says as many asfour hundred fifty million peopleacross Africa are at risk from meningitis.The new vaccine is called MenAfriVac.It can be given to childrenas young as one,which is earlier than vaccinescurrently used to fightmeningitis epidemics in Africa.Health workers launchedthe new vaccine in Burkina Fasoin West Africa.There are twenty-five countriesalong Africa's so-calledmeningitis belt from Senegal to Ethiopia.The hope is that peoplein all twenty-five countrieswill be protected against the diseaseby twenty-fifteen.And that's the VOA Special EnglishHealth Report.